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Low temperature membrane properties

Nafion properties at low and subzero temperatures wereexperimentally measured. Membrane water content was measured bysetting water activity = 1 and varying air pressure from 0 and0.96 atm at 30{degree sign}C. Water content in mol SO3-/mol H2O=14 and 22 was found when air pressure = 0 and 0.94 atm, respectively. Schroeder'sparadox did not exist in the absence of air. The state of waterwas shown to depend on the cooling rate, where melting andfreezing peaks were lower for a 10{degree sign}C/min coolingrate than for a1{degree sign}C/min cooling rate. The freezing peaks were -27and -16{degree sign}C for10 and 1{degree sign}C/min cooling scan rates. Membraneconductivity wasmeasured from 0 to 80{degree sign}C for 100% RHvapor-equilibrated and 0 and95{degree sign}C for liquid-equilibrated Nafion. Theliquid-equilibratedconductivity had an activation energy of 10.2 kJ/mol.


Onishi, L., & Newman, J. (2005). Low temperature membrane properties. ECS Transactions, 1(6), 365-374. https://doi.org/10.1149/1.2214507

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